A variety of threaded fasteners have been developed for use in orthopedic surgical procedures to secure bone fragments, reattach ligaments or soft tissue to bones, or to hold bones in relative position to one another. One variety of bone screws used in the vertebrae of the spine are called pedicle screws, so named because they are inserted into the pedicle of the vertebral body. Pedicle screws are commonly used along with rods and screws to immobilize a portion of the spinal column. In other applications, pedicle screws are inserted into a series of vertebrae and one or more metal rods are secured to the heads of the screws, typically using set screws or some other securing means.
Current pedicle screw designs require multiple steps to insure proper implantation into the vertebral body. Typically, an entry point is made into the pedicle using a high speed drill bit or an awl to create a pilot hole. In some instances, the pilot hole is enlarged using larger diameter drill bits. The pilot hole may then be probed with an instrument to detect any breaches in the pedicle wall. After the integrity of the pilot hole wall is confirmed, the pilot is then tapped to create a track in the hole wall for the screw to follow using a tap. Finally, the screw may be implanted into the prepared hole.
Every surgical procedure carries with it a risk of complications. Procedures which require multiple steps such as pedicle screw implantation create the potential for the patient to experience complications with each step. Additionally, the chances for a surgeon to make a mistake due to fatigue during long procedures involving multiple screws increases with the number of steps required for placement of each screw. Thus there is a need for an improved bone screw which reduces the number of steps required for implantation of the screw into bone.